Finding ID | Version | Rule ID | IA Controls | Severity |
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V-256047 | ARST-RT-000680 | SV-256047r882483_rule | Medium |
Description |
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MSDP peering with customer network routers presents additional risks to the DISN Core, whether from a rogue or misconfigured MSDP-enabled router. To guard against an attack from malicious MSDP traffic, the receive path or interface filter for all MSDP-enabled RP routers must be configured to only accept MSDP packets from known MSDP peers. |
STIG | Date |
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Arista MLS EOS 4.2x Router Security Technical Implementation Guide | 2023-01-17 |
Check Text ( C-59723r882481_chk ) |
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Review the Arista router configuration to determine if there is a receive path or interface filter to only accept MSDP packets from known MSDP peers. Step 1: Verify the MSDP peers and the corresponding interfaces. router msdp peer 10.11.12.2 ! peer 10.22.12.2 Step 2: Verify the access-list is configured inbound on MSDP peering interfaces. MSDP uses TCP port 639. Execute the command "sh ip access-list". ip access-list MSDP_FILTER 10 permit tcp host 10.1.12.2 host 10.11.17.9 eq 639 20 permit udp host 10.1.12.2 host 10.11.17.9 eq 500 30 permit udp 10.11.17.9 eq 500 host 10.1.12.2 40 deny ip any any log Step 3: Verify the ACL is applied on the interface. Execute the command "sh run int ethernet YY". interface ethernet 3 ip access-group MSDP_FILTER in If the Arista router is not configured to only accept MSDP packets from known MSDP peers, this is a finding. |
Fix Text (F-59666r882482_fix) |
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Ensure the receive path or interface filter for all Arista MSDP routers only accepts MSDP packets from known MSDP peers. Step 1: Configure the MSDP peers. LEAF-1A(config)#router msdp LEAF-1A(config-router-msdp)# peer 10.11.12.2 LEAF-1A(config-router-msdp)# peer 10.22.12.2 Step 2: Configure the access-list inbound on MSDP peering interfaces. MSDP uses TCP port 639. LEAF-1A(config-router-msdp-peer-10.22.12.2)#ip access-list MSDP_FILTER LEAF-1A(config-acl-MSDP_FILTER)# 10 permit tcp host 10.1.12.2 host 10.11.17.9 eq 639 LEAF-1A(config-acl-MSDP_FILTER)# 20 permit udp host 10.1.12.2 host 10.11.17.9 eq 500 LEAF-1A(config-acl-MSDP_FILTER)# 30 permit udp 10.11.17.9 eq 500 host 10.1.12.2 LEAF-1A(config-acl-MSDP_FILTER)# 40 deny ip any any log Step 3: Apply the ACL on the interface. LEAF-1A(config-acl-MSDP_FILTER)#interface ethernet 3 LEAF-1A(config-if-Et3)# ip access-group MSDP_FILTER in |